Aya has a shrine maiden's bloodline.Mother (Setsuko) tries to raise Aya into a shrine maiden at the expense of a bad younger brother (Tatsukuma).Aya, who is not aware, asks her mother while being puzzled, but eventually grows into a shrine maiden in the village.Even though he is unaware, he begins to see the scale as a slut everywhere, so he suffers from a sense of distance with the villagers.The more you suffer, the more your gender begins to control your body as a slut.
